Face Lifting & Rejuvenation
As human gets older, skin and its under structure tissues constantly get ageing process. Typically, number of fibroblast on the skin decreases and collagen synthesis also decreases. And functions and numbers of many skin appendage are also dropped. For under tissues of the skin that maintain the face contour also form laxity due to the aging process. Before learning more about face lifting using HIFU (High Intensity Focused Ultrasound), it is necessary to understand the face anatomy. Face and scalp are composed of several layers and these can be specifically composed into five standard layers(Figure 1).
[Figure 1. 5 Layers to compose face and scalp]
2) Subcutaneous layer
3) Musculoaponeurotic layer (SMAS: Superficial MusculoAponeurotic System)
4) Loose areolar tissue (ie, spaces and retaining ligaments)
5) Fixed periosteum and deep fascia
So far in the laser treatment area of dermatology, the epidermis and dermis were the main interested therapeutic areas for the skin treatment. However, collagen remodelling on deep dermis slightly helps to regain some degree of skin elasticity but it is difficult to improve its own fundamental face contour.
History of Face Lifting & Tightening
The Latin word ‘Rejuvenation‘ is the compound word of ‘Re’ and ‘Juvenile’ which can be interpreted ‘as a kid again’ or ‘be young again’. The proposition of ‘becoming young again’ is a human desire of all time. Also such development of the laser was developed to meet the wishes of human, and ‘rejuvenation’ is still somewhat a question to dermatologists.
The development of laser and other medical equipment for rejuvenation can be classified in many
different ways but can be largely categorized in five (Table 1, Figure 2).
|1||Ablative Resurfacing with Lasers|
|2||Photorejuvenation with IPL|
|3||Rejuvenation with Electrical Current (RF)|
|4||Rejuvenation with Fractional Laser|
|5||New Generation Rejuvenation with HIFU|
[Table 1. Developmental history of facial rejuvenation]
[Figure 2. History of Rejuvenation Devices (History of the device development by time frame and describes each device covering area)]
When the laser technology was not developed in old days, ablative laser or chemical peeling was used for face lifting. It was the time when we had to face all side effects through laser treatment. All these experiences and trials affect in the later days the development of next generation lasers. Due to serious side effects and downtime, these are narrowly treated nowadays. Along with development of IPL, interests were focused on ‘photorejuvenation’ but the effect was insignificant and it soon was dismissed in the market. But IPL has several advantages that it is still widely used in pigmentation, vascular, and hair removal.
The item that has been used for longest time in Rejuvenation is the ‘Radiofrquency’ of using electrical energy. It is either divided into MONOPOLAR or BIPOLAR. Only the RF was applied for the treatment or it was developed into a ‘hybrid form’ of adding other lasers like diode laser, IR, and IPL. In domestics, RF needle is now widely used as method of transferring electrical current fractionally. Most of Korean laser companies are manufacturing this ‘needling RF’.
Fractional laser is also the ‘rejuvenation item’ that has long run. There are many factional lasers with different wavelengths, such as 1,550nm(Er:glass fiber), 10,600nm(CO2), 2,940nm(Er:YAG) that are developed and applied for treatments.
‘HIFU’ is a new spotlight concept in these days. Without damaging the skin or the subcutaneous layer and its surrounding tissues, it makes ‘selective thermal coagulative zone’ on the subcutaneous layer and SMAS layer improving the skin aging. HIFU is a high intensity focused ultrasound that is transferred into deep structures, such as deep dermis, boundary layer of deep dermis and subcutaneous fat, fibrous tissues of subcutaneous fat, SMAS layer and fascia. And over the wound healing process for several months, a gradual face lifting effect can be achieved.
Conditions to the Ideal Rejuvenation Equipments
The most important condition to the rejuvenation equipment is ‘to minimize the side effect and to maximize the effect’. But so far, those of equipments showing dramatic results had relatively high risk of side effect (Figure 3).
[Figure 3.] Each Rejuvenation Device’s Correlation of Dramatic Result and Complication Risk:
So far, those of equipments having higher risk of side effects showed dramatic result. The development target of rejuvenation equipment is to minimize the side effect while maximizing the effect.
For the full face resurfacing using laser or chemical peeling, effect is positive in case of successful treatment but there were risk of nearly 100% side effects. As a result, high risk is high return.
Thus, far the most important matter in developing rejuvenation equipment is to minimize the side effect while maximizing the effect. And the closest equipment of this can be said as HIFU.
Concepts of HIFU
HIFU(High Intensity Focused Ultrasound)’ is not using the ‘light’ like other standard lasers but is
‘using ‘sound waves’ and is a new method in medical device. Frequency of the sound that human ear can hear is generally in the range of 16Hz~20kHz. If frequency exceeds 20kHz, it is called ultrasonic wave(Figure 4).
[Figure 4] Classification of Sound wave For Each frequency area:
If frequency exceeds 20kHz it is classified as ‘ultrasound’ , and ultrasound over 250kHz is classified as ‘high frequency ultrasound’. Ultrasound has a tendancy to transmit water and that allowed to use in ultrasound diagnostic units for long period of time in medical field. Recently ultrasound is widely used in not only the diagnostic unit but in therapy equipment.
The principles of ultrasonic applied in the treatment area is the physical effects of its ultrasound(Table 2).
[Table 2. Three Types of Physical Effects of Ultrasound]
1) Mechanical Effect
2) Cavitational Effect
3) Thermal Effect
2. History of HIFU
HIFU is to treat various cancers like liver cancer, uterine cancer, and breast cancer through thermal energy which is created in the focal point of supersonic wave, collected from the ultrasound transducer. At first it is developed to treat solid tumor but in later days it could get attention as non invasive treatment modality(Foster RS et al. High-intensity focused ultrasound in the treatment of prostatic disease. Eur Urol 1993;23:29–33).
3. Apply to the Skin Rejuvenation
HIFU makes ‘selective thermal coagulative change’ on subcutaneous layer and SMAS layer without damaging surrounding tissues. For other light based devices or RF devices, it was unavoidable to damage the epidermis and upper dermis to stimulate the deep dermis. However, HIFU does not effect the skin and subcutaneous layer at all but forms ‘thermal coagulative zone’ on only the deep dermis.
The first time of applying HIFU to skin rejuvenation was in 2007 by Gliklich(Gliklich RE et al. Clinical pilot study of intense ultrasound therapy to deep dermal facial skin and subcutaneous tissues. Arch Facial Plast Surg 2007; 9(2): 88–95). It begins to attract attention in detail when research data using body tissues was released in 2008 at Harvard Wellman Center(Laubach HJ et al. Intense focused ultrasound: evaluation of a new treatment modality for precise microcoagulation within the skin.
Dermatol Surg 2008; 34(5): 727–34). Research on facial skin tightening was announced but it was a limited research mainly on eyebrow-lifting (Alam et al. Ultrasound tightening of facial and neck skin. J Am Acad Dermatol 2010; 62(2): 262–9).
4. Principle of ‘Face Lifting’ using HIFU
When electrical energy is transferred to the ceramic of HIFU transducer, electrical energy transforms into ultrasound. And when this created ultrasound is focused, it generates thermal energy at ‘maximum focusing point’.
In other words, it only generate thermal energy on the ‘maximum focusing point’ and create ‘selective thermal coagulative zone’ on SMAS layer without damaging epidermis and subcutaneous tissues. These thermal coagulation zones react to high energy of over 60˚C. This causes the sagging skin tissues to contract and give skin tightening and lifting effects.
The actual coagulation zone after HIFU applied to real tissues
cf) Schlieren method: A way of making the light visible pattern of wave which is reflected by the change of density based on sound wave
To prove this, a test was carried out on a micro pig(femaile) having the most similar skin to human by emitting HIFU (Figure 5). Even in this animal experiment, selective coagulation zones from thermal damage were found.
Figure 5. HIFU Emitting pictures of before & after on ‘micro pig(female)’ tissues (H&E, stain X50)
A. Before Emitting HIFU
B. After Emitting HIFU : There is no damage on epidermis and tissues above dermis, and there is coagulation zone formed on subcutaneous layer where HIFU was emitted.
HIFU is high intensity focused ultrasound energy which is transferred fractionally to depth of skin that creates thermal damage on the deep structures like deep dermis, subcutaneous layer, fascia and
SMAS layer. And it will gradually lead to face lifting effect through few months of wound healing process.
Unlike the general HIFU of treating solid tumor, the HIFU that is used on the skin for rejuvenation purpose has very short exposure duration (in mili second). So the energy delivered to the target is also low(below 15J per pulse). As the ultrasonic is emitted in short time, it does not damage on epidermis and upper dermis but able to target the SMAS layer and deep dermis.
If exposure time(same as pulse duration) gets longer, thermal zone will be created on the skin surface in axial direction. Therefore, when it becomes longer, damages on skin surface is unavoidable. And so short exposure time is very important to treat the target more effectively by not hurting epidermis and upper dermis.
The biggest difference of HIFU from other lasers or light is that it is not related to skin color or chromophore(color blind). It is an advantage that it can do effective rejuvenation even on the dark skin, which was difficult to treat with light based treatment.
HIFU is the new concept therapy equipment for a truly ‘non invasive rejuvenation’.
To know more contact our expert cosmetic dermatologists to take a completely informed decision to find a new you with a young look a confident feel. call us now@ +91 9869041559 to book an appointment.